In optical fiber communication networks, easily detachable connectors are widely used for connection between optical fibers. The connection is provided by butting ferrules, which are used for positioning of the optical fibers, directly against each other. Given this, in order to reduce optical loss (communication loss) from the optical fiber after the connection, a connection end face of the optical fiber connector to be connected is required to have a sufficiently smooth surface and not to generate a gap between optical fibers at the connection end faces (not to have an undercut of the optical fiber with respect to the ferrule).
Polishing of such a connection end face of an optical fiber is performed in four steps of: removal of an adhesive; rough polishing of a spherical surface; intermediate finishing; and finish polishing. Of these, polishing accuracy of the step of finish polishing largely influences the optical loss. Furthermore, in light of productivity and production cost, an abrasive film used in the step of finish polishing is required to have a great grinding force.
As such an abrasive film, an abrasive film has been proposed having an abrasive layer containing a resin binder and abrasive particles. In order to meet these needs, attempts have been made such as selection of a type of the resin binder and of the abrasive particles, as well as increase in particle size of the abrasive particles (refer to Japanese Unexamined Patent Application, Publication Nos. H8-336758, 2002-239924, and 2007-190613).
However, using particles having a larger particle size as the abrasive particles in the abrasive film in order to obtain a great grinding force results in selective polishing of the optical fiber and makes it difficult to prevent an undercut of the optical fiber and to make the optical fiber to protrude from the ferrule, and a gap is more likely to be generated between the optical fibers at the connection end faces. Given this, in the Prior Art, the increased grinding force and prevention of an undercut of an optical fiber are not sufficiently concomitantly provided.